Etching printing rolls



April 11, 1944. J. J..ORMOND ETCHING PRINTING ROLL 2 Sheets-Sheet 1Filed Dec. 28, 1942 April 11, 1944.

J. J. ORMOND ETCHING PRINTING ROLL Filed Dec. '28, 1942 2 Sheets-Sheet 2Patented Apr. 11, 1944 ETCHIN G PRINTING ROLLS John J. Ormond, Boston,Mass., assignor 01' twothirds to Joseph D. Ramsey, Boston, Mass.

Application December 28, 1942, Serial No. 470.411

6 Claims.

This invention relates to printing and more especially to engravingprinting rolls of the type employed in textile color printing.

An object of the invention is to improve methods of etching printingrolls and more especially to devise a procedure for applying acid resistto rolls with a view to shortening the time ordinarily required for suchoperations, and to decreasing the number of etching operations resortedto. Another object of the invention is to provide a method of etchingwhich simultaneously forms different types of ground lines by means ofwhich two tones of color printing may be carried out on textiles andother materials. Another object is to provide a simple, cheap andeflicient method of etching.

The nature of the invention and its objects will be more fullyunderstood from the following description of the drawings and discussionrelating thereto.

In the accompanying drawings:

Fig. 1 is a view in side elevation illustrating a step in the method ofthe invention;

Fig. 2 is a cross sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a plan view illustrating another step in the method;

Fig. 4 is another cross sectional view taken on the line 44 of Fig. 3;

Fig. 5 is a view in side elevation illustrating another step in themethod;

Fig. 6 is a cross sectional view taken on the line 6-6 of Fig. 5; 7

Fig. 7 is a view in side elevation illustrating still another step inthe method referred to;

Fig. 8 is a cross section taken on the line 88 of Fig. 7;

Figs. 9, 10 and 11 are views in side elevation illustrating still othersteps in the method referred to; and

Fig. 12 is a view in side elevation illustrating a roll engraved inaccordance with the method of the invention.

In making textile printing rolls for printing dye colors, it is nowcustomary to obtain intaglio or etched printing surfaces by two etchingoperations. The first operation consists in etching an outline of anygiven design which may be desired. Such an outline is obtained bycoating the roll with asphaltum and cutting through the asphaltum anoutline of the design by means of a pantograph machine. Acid reagent, asiron perchloride, is allowed to etch into the copper roll through theoutline, and thereafter the etched outline tus obtained is filled withenamel or other acid resist. V

The second necessary etching operation, in the conventional method ofmaking a textile printing roll, consists in again coating the roll overits entire surface with a light asphaltum. When dry, diagonally disposedground lines are cut into the asphaltum coating by means of a. knurlingtool, or some other suitable apparatus. 1 Since these knurled groundlines extend throughout the surface of the roll, and both insideandoutside of the portions of the roll surface included. within thedesign outline, it becomes necessary to paint out with heavy asphaltumthose areas of the roll surfaceoccurring outside of .the design out:line Where no engraving is desired to take place. The roll, selectivelycoveredv with. heavy asphaltum, is then etched a second time to provideangularly disposed ground lines insideof the design outline, and theseground ,lines receive and print dye colors, thereby to furnish suitableshading or strength of the colors on a textile material.

The present invention generally includes the step of simultaneouslyetching design outlines and two or more types of ground lines,thuseliminating several independent etching; steps and painting ouoperations. The method consists in superimposing one upon another on acopper roll three diiferent acid-resist materials, eachvof which issoluble in a solvent not affecting the other two. Two of theacid-resistmaterialsare first applied in the form of diagonally disposedlines which extend in opposite directions from one another, and whichare appliedone over the other. The third acid-resist occursin the formof a coating completely covering the first two applied sets of diagonallines of resist materials. By the use of a pantograph at this point, adesign outline is cut through the several acid resists,laying bare anoutline portion of the copper roll surface. A second toneoutline withinthe first design outline is also cut through the resists to form an areain which a different ground is to be etched for variation in color tone.The area between the design outline and the shade outline is formed withground lines, as for example crossed lines, which when inked willfurnish a dark tone, while the area within the second tone outline isformed with ground lines, as for example a series of parallel lines,which when inked will furnish a light tone. p

Selective removal of the thirdacidr'esist from the area within thedesign outline and the second tone outline is first carried out touncover crossed lines of the two first applied resists. The acid resistmaking up one of the sets of lines is then removed from within thesecond tone outline only, and the plate is then etched.

Referring more in detail to the drawings, Figure 1 illustrates the stepof applying on the surface of a copper roll I a series of lines 2diagonally disposed between the ends of the roll and spaced apart toleave uncovered portions of the roll surface. These lines consist of anacid-resist material preferably made up of a substance such as beeswax.

One suitable manner of applying the beeswax in the for'in of linesconsists in first coating the roll I with beeswax heated to atemperature at which it is relatively liquid. The coating thus obtainedis allowed to cool andthe linesare formed by scoring the coating to formthe spaces 3, as illustrated in Fig. 1. Such scoring maybe carried outfor example by means of a knurling tool or in some other desired way.

In accordance with a further step in the method of the invention, asecond set of diagonal lines is applied over the first set of lines 2.This is accomplished in the manner diagrammatically illustrated by Figs.3-6 inclusive. of the drawings.

Considering this more fully, numeral 4 illustrates a transfer memberwhich may, for example, consists of a sheet of relatively hardsurfacedpaper, such as onion skin paper, one side of which has been coated withgelatin. Upon the gelatin coated side of the paper 4. is printed Numeral6 denotes the spaces occurring betweenthe lines 5.

The gelatin coated paper containing the ink lines 5 is then broughtinto. contact with the roll:

I in some suitable manner as by rolling the sheet thereagainst,thustransferring the ink lines. 5 over the ink-lines 2 in thelmannerillustratedin Figs. 5 and 6 of thedrawings. The-lines. 5 are applied insuch a manner that they extenddiagonally with respect to the ends of theroll I and.

oppositely to the lines 2, thus resulting. in the surface of-the roll Ipresenting a series of crossed lines between which occur. theinterrupted spaces.

3 of bare copper.

The acid-resist material making up the second set of diagonal lines- 5is allowed to dry. The entire surface of the roll, as well as the twosets of diagonal lines Z-and- 5, is then covered witha coating 6 ofanother acid-resist material which may, for example, consist of amixture of glycerin and mercurousnitrate (Figs. 7 and 8). The coating isdried and then subjected to the action of hydrogen chloride gas. meansof treating the coating consists in suspending the roll in a chambercontaining hydrogen gas. Exposure for a period'of several minutes issufiicient for purposes of the invention.

The treatment of hydrogen chloride gas converts the mercurous nitrate tomercurous chloride, which occurs in the form of a white crystalline masshaving the property of being substantially resistant to acid 'resistsemployed in etching copper rolls, as for example iron per- One suitablechloride. In addition, the mercurous chloride is soluble in reagentswhich do not affect the other resists noted.

The roll thus provided with three different acid resists on its surfaceis then formed with a design outline I, cut through each of the resiststo lay bare an outline portion of the copper roll surface. This cuttingoperation may be carried out, for example, by a pantograph machine ofthe type conventionally employed in making textile printing rolls. Othermeans of forming the design outline may be resorted to if desired.

A second outline 8, which I prefer to designate as a tone outline, isthen cut through the three acid resists at points within the firstdescribed design outline i. Fig. 9 diagrammatically illustrates thesteps of forming two different outlines, one within the other. Theseoutlines, for the sake of simplicity in describing and illustrating theinvention, consist of a relatively simple cross design. However, it isintended that such a showing may be illustrative of various other typesof designs, commonly employed in printing textile materials.

Selective removal of acid-resist materials is then carried out toprepare the roll for the final etching operation. Figs. 10 and 11diagrammatically illustrate one suitable method of removing selectiveamounts of acid-resist material. By means of a pad or other suitableelement, a solvent i'or mercurous chloride is lightly applied over thoseportions of the mercurous chloride coating 8 which occur within thedesign outline T, as illustrated in Fig. 10. One suitable solvent formercurous chloride is ammonium hydroxide. Other bases may be resortedto.

Upon dissolving away a. selective amount of the mercurous chloride inthe manner noted, there results an area on the surface of the rolldefined by the design outline I, in which two sets of diagonallyextending lines, opposed to one another, appear.

A further removal of acid-resist material making up one of these sets ofdiagonal lines is then carried out. This may be done for example bytreating the portion of the roll surface included within the outline 8with a solvent for one of the sets of lines, as for example theink lines5; A suitable solvent for the ink lines; 5 is turpentine or benzine, andother organic liquids, and such solvents may be applied by means of apad or brush lightly passed over the roll surface within the outlineportion 8.

After carrying out removal .of selective amounts of two different acidresists in the manner described, there remain an area includedwithintheoutline 8 which presents only portions of the lines 2 ofbeeswax andspaces 3.occurring therebetween. When this part of the rollis immersedin an acid reagent, it will be seenthat etching may proceed along theareas defined by the spaces 2 to form one set of ground lines.

In that part of the roll-surface occurring between the outline8and thedesign outline i,

there appear diagonal lines 2, andthe diagonal etching to take place inthe form of a grain" which will hold printing ink differently than thelines 3 which appear within the outline 8.

Thereafter the roll is immersed in the conventional manner in an etchingreagent such as iron perchloride, and etching is allowed to proceed fora desired period. After completion of etching, the various resists areremoved. Ammonium hydroxide dissolves away remaining portions of themercurous nitrate. Turpentine or other organic solvent removes the linesand hot water takes away the lines 2 of beeswax.

As a result of these operations there is obtained an etched outline 9and a second etched outline Ii] within the etched outline 9. Alsobetween the etched outlines 9 and ill occurs a multiplicity of etchedsquares H, and inside of the etched outline iii occurs a series ofetched lines [2.

These etched portions of the roll surface, when furnished with dyecolors in the manner common to textile printing operations, will printsuch colors on a textile material.

It will be observed that the etched ground lines l2 constitute one typeof grain which may be designed to hold a relatively larger amount of dyecolor than tiny etched squares ll, constituting a different type ofgrain occurring within the etched outline I0 and the etched outline 9.In this way, two tones or shades of a given dye color may be printed.

An outstanding feature of the invention is the step of simultaneouslyetching both outlines and two-tone ground lines. The improved method ofapplying resist material employing a series of different acid resists,each of which is soluble in a solvent not affecting the others, makespossible such a result.

Use of mercurous chloride in forming the coating 6 is intended to beillustrative of use of other chemical reagents, and their conversion toan acid-resistant condition; and the solvent ammonium hydroxide employedto dissolve the mercurous chloride, is intended to be illustrative ofother solvents employed in this way.

The various operations described are of a relatively simple character,may b quickly carried out and do not require the skill and attentionwhich are required for conventional pantograph operations, followed bypainting out with heavy asphaltum. By forming the two sets of outlinesin the manner described, the solvent materials may be rapidly brushed inor otherwise applied at desired points, thus saving considerable time aswell as affording a higher degree of accuracy and sharpness of outlinesubject matter.

While I have shown a preferred embodiment of the invention, it should beunderstood that Various modifications may be resorted to, as for examplein applying the method in connection with other types of etchingoperations or in other ways, while still continuing to adhere to thespirit of the invention as defined by the appended .claims.

I claim:

1. That improved method of engraving textile printing rolls whichcomprises applying an acidresist material, in the form of spaced-apartdiagonal lines, on the surface of the roll, then applying a secondacid-resist material in the form of diagonally extending lines whichcross the lines of the said first resist material, each of said appliedresist materials being insoluble in a sol vent of the other, coating theroll and crossed lines of the first two applied resist materials with athird resist material, said third resist material being soluble in asolvent which does not dissolve either of the two first applied resistmaterials, cutting a design through the several resist materials to laybare a portion of the roll surface, removing portions of the lastapplied resist coating at selected points on the roll surface, re-.

moving portions of the last applied acid-resist coating and portions oflines of one of the resist materials at other points, and thenetchingthe roll.

2. That improved method of engraving textile printing rolls whichcomprises applying on a copper roll a series of spaced-apart diagonallines of acid-resist material, applying a second series of oppositelyextending diagonal lines from the said first series of lines, coating athird resist material over both of the first and second series ofacid-resist lines, cutting a design outline through all of the resistmaterials, then selectively removing two of the resist materials atselected points within the outline, and then etching to form an engravedoutline and two or more different grain surfaces.

3. That improved method of engraving textile printing rolls whichcomprises applying a series of diagonally extending lines of a resistmaterial on the surface of the roll, applying a second series ofoppositely extending lines of a second resist material on the surface ofthe roll, coating the roll with a third resist material, each of saidresist materials being insoluble in solvents for the other twomaterials, cutting a design outline through the several resist materialsto lay bare a portion of the roll surface, cutting a second outlinewithin the said first outline, removing one of the resist materials fromthe space included within the first design outline and the secondoutline and then removing another of the acid-resist materials from thearea included within the said second outline and then etching.

4. That improved method of engraving textile printing rolls whichcomprises applying a resist material of beeswax in the form ofdiagonallyextending lines on the surface of the roll, applying a secondseries of diagonal lines of resist material over the said first lines,said second series of lines of acid-resist material consisting of anacid-resistant ink, coating the roll with mercurous nitrate, treatingthe mercurous nitrate with hydrogen chloride gas to convert themercurous nitrate to mercurous chloride, cutting a design outlinethrough the mercurous chloride, acid-resistant ink lines and lines ofbeeswax, cutting a second outline within the first outline, dissolvingwith ammonium hydroxide that portion of the mercurous chloride coatingoccurring within the said first formed outline, dissolving with anorganic solvent the ink lines included within the said second formedoutline, etching the roll, and then removing remaining resist materialsfrom the surface of the roll.

5. That improved method of engraving which comprises selectivelyapplying on the surface to be engraved a resist material, therebyleaving uncovered surfaces which, when etched, will provide a grain,applying a second resist material over the first resist material,thereby to leave uncovered surfaces which, when etched, will present asecond type. of grain, each of said resist materials being soluble insolvents which do not affect the others, applying a third resistmaterial over the said first and second resist materials, said thirdresist material being soluble in a solvent which does not affect thesaid first and second resist materials, said third resist material beinginsoluble with respect to solvents for the said first and second resistmaterials,

removing one or more of, the resist materials at selected. points in thesurface of the roll, and etching, thereby to provide a plurality oftypes of grained surfaces on the roll.

6. That improved method of engraving textiles printing rolls whichcomprises applying a resist material of beeswax on the surface of a rollto.

5 mercurous nitrate with hydrogen chloride gas to convert the mercurousnitrate to ,mercuroustchloride, removing portions of the mercurouschloride and underlying acid resists, and then etching.

JOHN J.., ORMON

